Water and oil-resistant,antistatic and abrasion-resistant finish for nylon fabrics

ABSTRACT

A WATER AND OIL-RESISTANT, ANTISTATIC AND ABRASION-RESISTANT FINISH IS IMPARTED TO A NYLON FABRIC, SAID NYLON PREPARED FROM HEXAMETHYLENEDIAMINE AND ADIPIC ACID OR ITS DERIVATIVES, BY APPLYING AN AQUEOUS EMULSION CONNTAINING A LONG CHAIN ALIPHATIC ISOCYANATE, AN ORGANIC FLUOROPOLYMER, AND A REACTION PRODUCT OF A WATER SOLUBLE POLYAMINE HAVING POLYALKYLENE OXIDE GROUPS AND AN EPOXIDE OR HALOHYDRIN COMPOUND AND CURING SAID COMPOSITION ON THE NYLON FABRIC AT TEMPERATURES IN EXCESS OF 300*F.

3,736,177 WATER AND OIL-RESISTANT, ANTISTATIC AND ABRASION-RESISTANT FINISH FOR NYLON FABRICS Norman S. Buchan, Chelmsford, and Gil M. Dias, Fall River, Mass., assignors to the United States of America as represented by the Secretary of the Army No Drawing. Filed May 12, 1971, Ser. No. 143,184 Int. Cl. B32b 27/06; C09j 3/16 U.S. Cl. 117-138.8 N 6 Claims ABSTRACT OF THE DISCLOSURE A water and oil-resistant, antistatic and abrasion-resistant finish is imparted to a nylon fabric, said nylon prepared from hexamethylenediamine and adipic acid or its derivatives, by applying an aqueous emulsion containing a long chain aliphatic isocyanate, an organic fluoropolymer, and a reaction product of a water soluble polyamine having polyalkylene oxide groups and an epoxide or halohydrin compound and curing said composition on the nylon fabric at temperatures in excess of 300 F.

BACKGROUND OF THE INVENTION This invention relates to a process of treating nylon fabrics, fibers and yarns to improve or modify certain properties of such textile materials. More particularly, this invention relates to a process that provides a water and oil-resistant, antistatic and abrasion-resistant finish for nylon fabrics.

Finishing agents are frequently utilized in the textile industry to change or modify ch'emical and physical properties of fiber polymers, as well as yarns and fabrics made therefrom. Nylon, for example, while not considered to be a water absorbent material, can, due to capillarity, adsorb or transport liquids having low surface tension on their surfaces which in some cases will result in the adsorption of as much as 40% by weight of water on a woven fabric. Another undesirable property that nylon has in common with some other synthetic or natural polymers is the ability to accumulate and retain electrostatic charges, said charges being produced by frictional engagement between fibers, yarns or fabrics. Such electrostatic charges are not readily dissipated and are especially troublesome in articles of clothing. Finishing agents are known which can provide an oil and water-resistant finish or an antistatic finish. See, for example, United States Pat. No. 3,347,812 which issued Oct. 17, 1967 to De Marco and Dias which discloses a relatively permanent oil and water-resistant finish. United States Pat. No. 3,108,011 which issued Oct. 22, 1963 to Frotcher describes a process and composition for applying an antistatic finish to textile materials. Unfortunately, most finishing agents must be applied separately, are not compatible in combination, are relatively impermanent as finishes and result in the impairment or loss of other desirable textile properties.

SUMMARY Nylon fabric, said nylon being the product of hexamethylenediamine and adipic acid or its derivatives is provided with an oil and water-resistant and antistatic finish that is resistant to laundering. A coating composition described, in detail hereinafter, is applied to the fabric and cured on the fabric at elevated temperatures. This finishing process unexpectedly results in a significant improvement in the abrasion-resistant properties of nylon fabric.

United States Patent O 3,736,177 Patented May 29, 1973 DESCRIPTION OF THE PREFERRED EMBODIMENTS The nylon fibers, yarns and fabrics which are treated in accordance with the present invention are formed from high tenacity, continuous filament nylon prepared by the condensation of hexamethylenediamine with adipic acid or its derivatives. The filament has a melting point of 250i6 C. Any fabric constructed from the foregoing nylon material may be used in connection with this invention. One particular fabric is described in detail in military Specification, MIL-C-l2369D (GL), entitled Cloth, Ballistic, Nylon. This fabric is constructed with warp and filling yarns of 1050 denier, being multifilament with 3 to 4 turns per inch Z twist and the weave is a 2 by 2 basket weave with two ends weaving as one and two picks weaving as one.

The process of this invention requires the impregnation of the described nylon textile material with a liquid finishing agent composition, removal therafter of excess liquid from the nylon by conventional means to obtain the desired wet pick-up, drying the composition on the fabric and, finally, curing at elevated temperatures to fix the finish to the nylon. The finished nylon is thereupon washed and dried to remove unreacted materials.

The liquid finishing agent composition contains a mixture of (1) a long chain aliphatic isocyanate which can be heat cured at elevated temperatures, (2) an organic fiuoropolymer or copolymer, (3) the reaction product of water-soluble polyamines containing polyalkylene oxide radicals with compounds containing one or more epoxide and/or halohydrin groups, and (4) an emulsifying agent.

Long chain aliphatic isocyanates suitable for use in the foregoing composition and in this invention include polyisocyanates and polymers prepared from such polyisocyanates having the following idealized structural formula:

where y is 0 or 1, x is an integer of 2 to about 4 and R is the hydrocarbon group of polymeric fat acids, said polymen'c fat acids having been prepared by polymerizing fat acids of 8 to 24 carbon atoms. Examples include polyisocyanates such as OCNDNCO and where D is the divalent hydrocarbon group of dimeric fat acids, said dimer prepared by polymerizing fat acids of 8 to 24 carbon atoms, such as oleic and linoleic acids. Further examples of polyisocyanates and the processes for the synthesis of such compounds is disclosed in United States Pat. No. 3,455,883, which issued July 15, 1969 to Kamal and Rogier. An example of the foregoing that is commercially available is DDI 1410, a product of General Mills, Inc.

The organic fiuoro-polymers which may be used as a component of the liquid composition herein include any of the fiuoro-polymers which are known to provide water and oil-resistant properties. Fluoro-polymers of this type are disclosed, for example, in United States Pat. No. 2,803,615 to Ahlbrecht et al., United States Pats. Nos. 3,256,231 and 3,256,230 to Johnson and Raynolds, and United States Pats. Nos. 3,282,905 and 3,378,609 to Fasick et a1. Such materials are commercially available e.g. FC-208 and FC-2l0 products of 3M Company, and Zepel B a product of E. I. du Pont de Nemours & Company. Especially useful are polymers selected from (1) a polymer mixture consisting of (a) about 3% to about 25% by Weight of a polymer prepared from at least one polymerizable compound of the following structure:

in which n is an integer from 3 to 14 and (b) about 75% to about 97% by weight of a polymer prepared from at least one polymerizable vinyl monomer, or (2) a polymer mixture containing (a) at least one copolymer prepared from about 25% to about 99% by weight of at least one polymerizable compound containing fluorine of the following structure:

C F CH CH O CC CH CH in which n is an integer of from 3 to 14 and from 1% to about 75% by weight of at least one other polymerizable vinyl monomer and (b) a polymer prepared from at least one polymerizable vinyl monomer whereby the weight proportion between the said copolymer and said vinyl derived polymer is such that the mixture contains at least 12% by weight of the fluorine copolymer, and (3) a mixture of (1) and (2). An example of the foregoing is a mixture of a copolymer obtained by copolymerizing equal parts of C F CH CH O CC(CH )=CH C F CH CH O CC(CH :CH and with a homopolymer of C H O CC(CH =CH Other examples are set forth in United States Pat. No. 3,347,812 to De Marco and Dias and include (1) a mixture of 10% by weight of and Of C H O CC(CH )=CH and a mixture Of by weight of a copolymer of 50% and 50% c n cn clr o cc cH )-=cH and 88% by weight of CH17O2CC(CH3)=CH2.

The third component of the liquid composition is a reaction product of (a) water-soluble polyamines containing polyalkylene radicals attached to the nitrogen atom and having in the molecule more than one reactive hydrogen atom attached to a nitrogen atom and (b) compounds containing more than one epoxide and/or halohydrin group. Examples of the latter compounds include epichlorohydrin and dichlorohydrins as well as their reactive reaction products which contain more than one epoxide and/or halohydrin group in the molecule, such as reaction products of epichlorohydrin or dichlorohydrin with glycols, diglycols, polyalkylene oxides, glycerine, dicarboxylic acids, polycarboxylic acids, polyvalent phenols and the like. Examples of the former compounds include monoand bis-chlorohydrin ethers of polyalkylene oxides, monoand bis-glycidyl ethers of polyalkylene oxides condensed with polyamines such as ethylene diamine, dipropylene triamine, triethylene tetramine and the like. Examples of the foregoing compounds are disclosed in United States Pat. No. 3,108,011 to Frotscher. Specific examples of the reaction products include polyglycol-bischlorohydrin ether condensed with a dipropylene triamine, polyglycol-bis-chlorohydrin ether condensed with triethylene tetramine, and the oxyalkylation product of ethylene chlorohydrin condensed with dipropylene and reacted with epichlorohydrin. An example of a commercially available material is Stanax, a product of Standard Chemical Products, Inc.

The foregoing components of the composition are combined to form an aqueous emulsion that is stable for at least six hours without settling out. This stability is achieved by the addition of the small amount of a nonionic emulsifying agent and by maintaining the pH of the composition at or below 7 and preferably at a pH between 5.5 to 7.0. The isocyanate component is present in the composition in an amount from 30 to 42% by weight, the fluoropolymer in an amount from 10 to 18% by weight and the reaction product of the water-soluble polyamine in an amount of from 40% to about 60% by weight, said 4 percentages being based on the total weight of the three components.

EXAMPLE I There was prepared a liquid finishing composition for use in the present invention having the following composition:

(l) 5% by weight of DDI 1410, a long chain aliphatic isocyanate, (2) 2% by weight Zepel B, an organic fluoropolymer, (3) 7% by weight of Stanax, a reaction product of a water-soluble polyamine containing polyalkylene groups with compounds containing more than one epoxide or halohydrin group, (4) 0.5% by weight of a nonionic, emulsifying agent, nonylphenoxypoly (ethyleneoxy) ethanol, (5) 3.7% by weight sodium bicarbonate, and (6) 76.8% by weight of water. DDI 1410 and the emulsifying agent are mixed together and A of the available water is added with stirring. Zepel B is stirred into the foregoing mixture. Stanax is dissolved in /2 of the remaining water and sodium bicarbonate is dissolved in the remaining portion of the water. The Stanax and sodium bicarbonate solutions are combined with stirring and this solution is added to the DDI 1410, water emulsion with stirring.

EXAMPLE II Nylon cloth, 14.0 02. (a ballistic nylon fabric constructed in accordance with Military Specification MIL- C-12369D) was padded with the emulsion of Example I which emulsion was maintained at a temperature of F. and a pH of 6:0. The fabric was padded at the rate of 35 yards per minute, receiving 2 dips and 1 dip (14 tons pressure) between a steel and hard rubber roll to achieve a 30% wet pick-up. Leaving the padder, the wet fabric entered an infrared pre-heater at 250 F. then to a clip tenter frame where the fabric is dried at 250 F. The fabric passes through a roller-type gasfired oven and the finish is cured at 350 F. The cured treated fabric is subjected to an after wash at 160 F. with a wetting agent and then rinsed at 100 F. A 10 minute sour with 2% sodium silica fluoride was followed by a 10 minute rinse and a final drying at 300 F. The theoretical percentage add-on was 3.0% for the DB1 1410, 0.6% for the Zepel B and 2.0% for the Stanax components.

EXAMPLE III Nylon fabric finished as in Example II was examined to determine the water-resistance of the finish by exposure of the fabric to 1 inch per hour or rainfall for a period of 20 hours in a specially constructed rain room. The finished fabric was compared with the same nylon fabric unfinished, and with 14 oz. cotton duck conforming to Federal Specification CCCC-419C. The fabrics were placed on the rain room floor and exposed to the rainfall. The fabrics were removed and the gain in weight due to adsorbed or absorbed water was determined by comparing the dry original weight of the fabric with the weight of the fabric after exposure to the rainfall. The wet pick-up is expressed in Table I as the percentage increase in weight and is the average for two samples for each material. The results demonstrate that nylon finished according to this invention picks up less than A: as much water as the untreated nylon and approximately as much as the cotton duck.

After 15 launderings in a rotary, reversible, cylinder washer, with 3 wash cycles with detergent at temperatures of 100 F, F., and F. followed by 3 rinses at 140 F., 120 F. and 100 F. for each laundering, there was no decrease in water resistance in the nylon fabric finished in accordance with this invention.

EXAMPLE IV The abrasion-resistance of the nylon fabric finished according to this invention was ascertained by testing with a Taber Abrasion Tester in accordance with Federal Test Method Standard No. 191, Method 5306, which determines the number of abrasion cycles required to produce a specified state of destruction. Table II below indicates the number of cycles of abrasion required to abraid through the fabric. This test demonstrates the wholly unexpected and significant improvement in abrasion-resistance of nylon fabric finished in accordance with Example II as compared with the same nylon fabric unfinished and 14 oz. cotton duck.

TABLE II Fabric: Number of cycles for abrasion Nylon-finished 6,851 Nylon-unfinished 1,828 Cotton duck 2,177

Electric resistivity influences the accumulation of electric charges on a fabric. Electric resistivity of fabrics is measured in accordance with Standard Test Method of the American Association of Textile Chemists and Colorists (AATCC) 761964. Low resistivity is equated with good antistatic properties. The resistivity of the nylon finished according to Example II was 6.8 ohms/ square and after launderings as described in Example III, the resistivity was 9.8)(10 ohms/square, demonstrating good antistatic properties which are stable to repeated launderings.

We claim:

1. The process of imparting a water and oil-resistant, antistatic and abrasion-resistant finish to nylon fabric prepared from hexamethylenediamine and adipic acid or its derivatives which comprises:

(i) applying to said fabric an aqueous emulsion having a pH not in excess of 7 containing:

(a) 30% to 42% of a long chain aliphatic isocyanate, having the following structure:

3-E( z) ]x where y is 0 or 1, x is an integer of 2 to about 4, and R is the hydrocarbon group of polymer fat acids, said polymeric fat acids having been prepared by polymerizing fat acids of 8 to 24 carbon atoms,

'(b) 10% to 18% of an organic fluoro-polymer having water and oil-resistant properties,

(c) 40% to 60% of a reaction product of (A) water soluble polyamines containing polyalkylene oxide groups attached to the nitrogen atom and having in the molecule more than one reactive hydrogen atom attached to a nitrogen atom and (B) compounds containing more than one epoxide or halohydrin radicals, said percentages expressed as weight percentages of these three components in the composition,

(d) a nonionic emulsifying agent,

(e) sodium bicarbonate and (f) water.

(ii) drying said aqueous emulsion on said fabric and (iii) curing said coated fabric at elevated temperatures.

2. A process according to claim 1 wherein said organic fiuoro-polymer is a fluoro-polymer mixture selected from 1) a polymer mixture consisting of (A) about 3% to about 25% by weight of a polymer prepared only from compounds of the following structure:

E CnF2n+1CH2GH202CO=GH2 in which n is an integer from 3 to 14, and (B) about to about 97% by weight of a polymer prepared from at least one polymerizable vinyl monomer other than monomers of part (A) above, (2) a polymer mixture containing (A) at least one copolymer consisting of about 25 r to about 99% by weight of at least one polymerizable fluorine-containing compound of the following structure:

Cu F2n-HCH2CHZ 020 0:0 Hz

in which n is an integer of from 3 to 14 and from 1% to about 75 by weight of at least one other polymerizable vinyl monomer and (B) a polymer prepared from at least one polymerizable vinyl monomer other than the monomer of part (2)(A), whereby the weight proportion between the said copolymer and said vinyl derived polymer is such that the mixture contains at least 12% by weight of said copolymer containing fluorine, and (3) a mixture of (1) and (2).

3. A process according to claim 2 wherein said finish is cured on said fabric at a temperature of at least 300 F.

4. A process according to claim 3 wherein the wet pickup by said fabric of said aqueous emulsion is of at least 30% by weight.

5. A process according to claim 4 wherein the pH of said aqueous emulsion is in the range of from 5.5 to 7.0.

6. A process according to claim 5 wherein said aqueous emulsion contains 5% by weight of component (a), 2% by weight of component (b), 7% by weight of component (c), 0.5% by weight of component (d), 3.7% by weight of component (e) and 76.8% by weight of component (f).

References Cited UNITED STATES PATENTS 2,965,517 12/1960 Albrecht et al. 117139.5 X 2,982,751 5/1961 Anthes 117139.5 X 3,108,011 10/1963 Frotcher 117138.8 X 3,347,812 10/1967 De Marco et al. 17-1355 X 3,522,195 7/1970 Chao 117138.8 X 3,639,296 2/1972 Frotscher et a]. 117138.8 3,378,609 4/ 1968 Fasick et al. 26029.6 X 3,547,856 12/1970 Tandy 117-138.8 3,645,989 2/1972 Tandy 117138.8 3,455,883 7/1969 Kamal et al. 260--453 X WILLIAM D. MARTIN, Primary Examiner S. L. CHILDS, Assistant Examiner US. Cl. X.R.

117l39.5 A, 139.5 CQ 

